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Commit 10a07d81 authored by Artem Egorkine's avatar Artem Egorkine Committed by Greg Kroah-Hartman
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ALSA: line6: correct midi status byte when receiving data from podxt 



commit 8508fa2e7472f673edbeedf1b1d2b7a6bb898ecc upstream.

A PODxt device sends 0xb2, 0xc2 or 0xf2 as a status byte for MIDI
messages over USB that should otherwise have a 0xb0, 0xc0 or 0xf0
status byte. This is usually corrected by the driver on other OSes.

This fixes MIDI sysex messages sent by PODxt.

[ tiwai: fixed white spaces ]

Signed-off-by: default avatarArtem Egorkine <arteme@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20221225105728.1153989-1-arteme@gmail.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0e727c32

sound/usb/line6/driver.c

+2 −1
Original line number Diff line number Diff line
@@ -303,7 +303,8 @@ static void line6_data_received(struct urb *urb) 
		for (;;) {

			done =

				line6_midibuf_read(mb, line6->buffer_message,

						LINE6_MIDI_MESSAGE_MAXLEN);

						   LINE6_MIDI_MESSAGE_MAXLEN,

						   LINE6_MIDIBUF_READ_RX);



			if (done <= 0)

				break;

sound/usb/line6/midi.c

+2 −1
Original line number Diff line number Diff line
@@ -56,7 +56,8 @@ static void line6_midi_transmit(struct snd_rawmidi_substream *substream) 


	for (;;) {

		done = line6_midibuf_read(mb, chunk,

					  LINE6_FALLBACK_MAXPACKETSIZE);

					  LINE6_FALLBACK_MAXPACKETSIZE,

					  LINE6_MIDIBUF_READ_TX);



		if (done == 0)

			break;

sound/usb/line6/midibuf.c

+17 −8
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


#include "midibuf.h"





static int midibuf_message_length(unsigned char code)

{

	int message_length;
@@ -20,12 +21,7 @@ static int midibuf_message_length(unsigned char code) 


		message_length = length[(code >> 4) - 8];

	} else {

		/*

		   Note that according to the MIDI specification 0xf2 is

		   the "Song Position Pointer", but this is used by Line 6

		   to send sysex messages to the host.

		 */

		static const int length[] = { -1, 2, -1, 2, -1, -1, 1, 1, 1, 1,

		static const int length[] = { -1, 2, 2, 2, -1, -1, 1, 1, 1, -1,

			1, 1, 1, -1, 1, 1

		};

		message_length = length[code & 0x0f];
@@ -125,7 +121,7 @@ int line6_midibuf_write(struct midi_buffer *this, unsigned char *data, 
}



int line6_midibuf_read(struct midi_buffer *this, unsigned char *data,

		       int length)

		       int length, int read_type)

{

	int bytes_used;

	int length1, length2;
@@ -148,9 +144,22 @@ int line6_midibuf_read(struct midi_buffer *this, unsigned char *data, 


	length1 = this->size - this->pos_read;



	/* check MIDI command length */

	command = this->buf[this->pos_read];

	/*

	   PODxt always has status byte lower nibble set to 0010,

	   when it means to send 0000, so we correct if here so

	   that control/program changes come on channel 1 and

	   sysex message status byte is correct

	 */

	if (read_type == LINE6_MIDIBUF_READ_RX) {

		if (command == 0xb2 || command == 0xc2 || command == 0xf2) {

			unsigned char fixed = command & 0xf0;

			this->buf[this->pos_read] = fixed;

			command = fixed;

		}

	}



	/* check MIDI command length */

	if (command & 0x80) {

		midi_length = midibuf_message_length(command);

		this->command_prev = command;

sound/usb/line6/midibuf.h

+4 −1
Original line number Diff line number Diff line
@@ -8,6 +8,9 @@ 
#ifndef MIDIBUF_H

#define MIDIBUF_H



#define LINE6_MIDIBUF_READ_TX 0

#define LINE6_MIDIBUF_READ_RX 1



struct midi_buffer {

	unsigned char *buf;

	int size;
@@ -23,7 +26,7 @@ extern void line6_midibuf_destroy(struct midi_buffer *mb); 
extern int line6_midibuf_ignore(struct midi_buffer *mb, int length);

extern int line6_midibuf_init(struct midi_buffer *mb, int size, int split);

extern int line6_midibuf_read(struct midi_buffer *mb, unsigned char *data,

			      int length);

			      int length, int read_type);

extern void line6_midibuf_reset(struct midi_buffer *mb);

extern int line6_midibuf_write(struct midi_buffer *mb, unsigned char *data,

			       int length);

sound/usb/line6/pod.c

+2 −1
Original line number Diff line number Diff line
@@ -159,8 +159,9 @@ static struct line6_pcm_properties pod_pcm_properties = { 
	.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */

};





static const char pod_version_header[] = {

	0xf2, 0x7e, 0x7f, 0x06, 0x02

	0xf0, 0x7e, 0x7f, 0x06, 0x02

};



static char *pod_alloc_sysex_buffer(struct usb_line6_pod *pod, int code,